Non-marking clamp



Feb. 4, 1964 E. s. OLSEN 3,120,046

NON-MARKING CLAMP Filed Nov. 15, 1961 2 Sheets-Sheet 1 INVENTOR.

2 Sheets-Sheet 2 Filed NOV. 15, 1961 NVENTOR.

United States Patent 3,120,046 N (IN-MARKING CLAMP Edwin Shirl filsen, fialt Lake City, Utah, assignor to Chicago Bridge 8: iron t-Iornpany, Chicago, Ill., a corporation of Illinois Filed Nov. 15, 1961, Ser. No. 152,585 Claims. (Cl. 24-448) This invention relates to a clamping device which is adapted for clamping and carrying a load. One of the primary features of the invention is to provide a clamping device which will carry a large load and, at the same time, will not mar the clamped surfaces to the extent that those surfaces require refinishing. Moreover, the clamping device of the invention exerts a holding :force on the load which increases as the load increases.

The clamping device of the invention is particularly adapted to carrying a load such as a large steel plate weighing, for example, about five tons. When such large loads are clamped and carried by prior art devices severe mam-ring of the clamped surfaces has been found to result.

In a specific embodiment of the clamping device employed in carrying out the invent-ion, a generally C-shaped clamp body having a pair of arm pontions terminating in a bight portion is provided. One of the arm portions is provided with a clamping screw having a freely rotatable pressure plate which is adapted to engage one surface of the load, while the other arm is provided with a cam which is adapted to engage the other and opposite surface of the load. The load is positioned between the pressure plate and the cam and the clamping screw is then tightened. As the load is raised by the clamping device, the cam is rotated by the load into increasing contact with the load.

The load engaging surfaces of the pressure plate and cam are preferably roughened to increase the gripping action.

In another embodiment of the clamping member, the carrying force exerted on the clamping member is offset from a center line disposed medially between the arm portions and passing through said bight portion, thereby augmenting the eifect attained in the construction of the other embodiment.

Having genes-ally described the invention, reference is now made to the accompanying drawings in which:

FIGURE 1 is a diagrammatic view showing the manner in which the clamping device of the invention is employed;

FIGURE 2 is an elevation view showing the clamping device with the load clamped therein;

FIGURE 3 is a cross-sectional view taken along line 3-3 of FIGURE 2;

FIGURE 4 is a side elevation view showing a modified view of the clamping den/ice of the invention;

FIGURE 5 is a side elevation view showing the internal details of the clamping device; and

FIGURE 6 is a cross-sectional view taken along line 6-6 of FIGURE 5.

Referring now to FIGURE 1 of the drawings, there is shown a clamping device 10 for clamping and carrying a load L. The load is shown to be a large steel plate but it is apparent that various types of loads are adapted to be clamped and carried. The clamping device 163 is suspended by what is shown to be a chain 11 from a carrying structure shown to be a crane 12.

Referring now to FIGURE 2 of the drawings, the clamping device 10 is shown tohave a generally 0- shaped clamp body 13 which comprises arm portions 14- and 15 terminating in a bight portion 16. A clamping screw 17 is threadably received in the arm portion 14. The clamping screw 17 has a pressure plate 18 secured thereto between the arm portions 14 and 15. The presice sure plate 18 is provided with a shoulder 19 which abuts the other terminal end 20 of the clamping screw 17, while a reduced portion 21 is fitted for relative rotation in a bore 22 of the clamping screw 1?. The pressure plate 18 contains a stepped bore 23 which receives a shouldered threaded fastener 24. The load engaging surface 1&1 of the pressure plate 18 is preferably roughened as, for example, by knurling so that the load can be better gripped. The other end of the clamping screw 17 terminates in a terminal end 17a shown to have an aperture 17b therein. A suitable tool T can be fitted into the aperture 17b for turning the clamping screw 17. Any suitable means, however, can be employed to rotate the clamping screw 17.

The arm portion 15 contains a bore 25 which acts as a bearing for a shaft '26 to which a cam 27 is secured. The shaft 26 is provided with cutout portions 28 and 29 of limited extent. Stops 3-1 and 32 are threaded into the arm portion =15 and terminate in the cutout portions 28 and 29. The stops 31 and 32 limit the angular rotation of the shaft 26 and hence of the cam 27. The surface 32 of the cam 27 which is adapted to engage the load L is preferably roughened for example by k-nuuling so that the load L can he better gripped. A passage 33 is provided in the clamp body 13. The passage 33 receives a light spring 34 which is attached at one end to the cam 27 by a pin 35 and at the other end by a pin 36 which is anchored in the clamp body 13. The spring 84 serves to return the cam 27 to a rest position when the clam ing screw 17 is loosened with respect to the load L.

An aperture 37 is shown in FIGURE 2 of the drawings to be disposed along a center line which passes generally medially between the arm portions 14 and 15 and which passes through the bright portion 16. A link 38 is shown to pass through the aperture 37 whereby the clamping device 10 with its load L is adapted to be carried. Although an aperture 37 has been shown to provide the means whereby the clamping device iii is carried, any suitable means, for example, a pair of outwardly extending lugs are employable for this purpose.

In the embodiment of FIGURES 4, 5 and 6, there is shown an aperture 39 which serves the same general purpose as the aperture 37 of the embodiment of FIG- URE 2. However, the aperture 39 is offset from a center line CL disposed medially between the arm portions 14 and 15 which passes through the bight portion '16. The apenture 39 is offset in a direction which is opposite the direction in which the cam 27 extends from the center line CL. By this construction, a moment is placed on the load which augments the clamping effect of the pressure plate 18 and the cam 27.

In both of the embodiments of the invention it is apparent that the load L energizes the cam 27 into increasing clamping cont act with the load L when a force is applied to the clamp body 13 which is generally opposite the gravitational force exerted by the load L.

The above-described embodiments being exemplary only, it will be understood that various modifications in form or detail will be readily apparent to one skilled in the art. Accordingly, the invention is not to be considered as limited save as is consonant with the scope of the following claims.

What is claimed is:

l. A clamping device adapted for clamping and carrying a load comprising: a generally C-shaped clamp body having a pair of arm portions terminating in a b ight portion, a clamping screw threadably received in one of said arm portions, a pressure plate freely rotatably mounted at one end of said clamping screw between said arm portions, a cam rotatably mounted in the other of said arm portions generally opposite said pressure plate, said cam being rotated into increasing clamping contact with the load when a force is applied to said clamp body which is generally opposite the gravitational force exerted by the load; and spring means, having one end secured to said cam and the other end secured to said bight portion, for automatically rotating said cam out of increasing clamping contact when said clamping screw is actuated to release the load.

2. The invention defined in claim 1 including means to which a load carrying member is adapted to be attached.

3. The invention defined in claim 1 including means offset from a center line disposed generally medially between said arm portions and passing through said bight portion to which a load carrying member is adapted to be attached.

4. The invention defined in claim 1 including means for limiting the rotational movement of said cam.

5. The invention defined in claim 1, said pressure plate and said cam having roughened load-engaging faces.

References Cited in the file of this patent UNITED STATES PATENTS 862,114 Skinner July 30, 1907 1,262,300 Blake Apr. 9, 1918 1,279,274 Comrie Sept. 17, 1918 1,327,673 Heckman Jan. 13, 1920 1,376,856 Boardman May 3, 1921 1,705,902 Dautch Mar. 19, 1929 1,779,427 Giillet Oct. 28, 1930 1,837,990 Otis Dec. 22, 1931 2,006,949 Hockensm-ith July 2, 1935 2,429,358 Kamiss Oct. 21, 1947 2,654,630 Renfroe Oct. 6, 1953 3,057,032 Harding Oct. 9, 1962 3,074,753 Gardner Jan. 22, 1963 

1. A CLAMPING DEVICE ADAPTED FOR CLAMPING AND CARRYING A LOAD COMPRISING: A GENERALLY C-SHAPED CLAMP BODY HAVING A PAIR OF ARM PORTIONS TERMINATING IN A BIGHT PORTION, A CLAMPING SCREW THREADABLY RECEIVED IN ONE OF SAID ARM PORTIONS, A PRESSURE PLATE FREELY ROTATABLY MOUNTED AT ONE END OF SAID CLAMPING SCREW BETWEEN SAID ARM PORTIONS, A CAM ROTATABLY MOUNTED IN THE OTHER OF SAID ARM PORTIONS GENERALLY OPPOSITE SAID PRESSURE PLATE, SAID CAM BEING ROTATED INTO INCREASING CLAMPING CONTACT WITH THE LOAD WHEN A FORCE IS APPLIED TO SAID CLAMP BODY WHICH IS GENERALLY OPPOSITE THE GRAVITATIONAL FORCE EXERTED BY THE LOAD; AND SPRING MEANS, HAVING ONE END SECURED TO SAID CAM AND THE OTHER END SECURED TO SAID BIGHT PORTION, FOR AUTOMATICALLY ROTATING SAID CAM OUT OF INCREASING CLAMPING CONTACT WHEN SAID CLAMPING SCREW IS ACTUATED TO RELEASE THE LOAD. 